Support serialization of WorldImpact

pkg/compiler/lib/src/js_backend/native_data.dart

+// Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+library js_backend.native_data;
+
+import '../common.dart';
+import '../elements/elements.dart' show
+    ClassElement,
+    Element,
+    FunctionElement,
+    MemberElement;
+
+/// Additional element information for native classes and methods and js-interop
+/// methods.
+class NativeData {
+  /// The JavaScript names for elements implemented via typed JavaScript
+  /// interop.
+  Map<Element, String> jsInteropNames = <Element, String>{};
+
+  /// The JavaScript names for native JavaScript elements implemented.
+  Map<Element, String> nativeMemberName = <Element, String>{};
+
+  /// Tag info for native JavaScript classes names. See
+  /// [setNativeClassTagInfo].
+  Map<ClassElement, String> nativeClassTagInfo = <ClassElement, String>{};
+
+  /// Returns `true` if [element] is explicitly marked as part of JsInterop.
+  bool _isJsInterop(Element element) {
+    return jsInteropNames.containsKey(element.declaration);
+  }
+
+  /// Returns [element] as an explicit part of JsInterop. The js interop name is
+  /// expected to be computed later.
+  void markAsJsInterop(Element element) {
+    jsInteropNames[element.declaration] = null;
+  }
+
+  /// Sets the explicit js interop [name] for [element].
+  void setJsInteropName(Element element, String name) {
+    assert(invariant(element,
+        isJsInterop(element),
+        message:
+          'Element $element is not js interop but given a js interop name.'));
+    jsInteropNames[element.declaration] = name;
+  }
+
+  /// Returns the explicit js interop name for [element].
+  String getJsInteropName(Element element) {
+    return jsInteropNames[element.declaration];
+  }
+
+  /// Returns `true` if [element] is part of JsInterop.
+  bool isJsInterop(Element element) {
+    // An function is part of JsInterop in the following cases:
+    // * It has a jsInteropName annotation
+    // * It is external member of a class or library tagged as JsInterop.
+    if (element.isFunction || element.isConstructor || element.isAccessor) {
+      FunctionElement function = element;
+      if (!function.isExternal) return false;
+
+      if (_isJsInterop(function)) return true;
+      if (function.isClassMember) return isJsInterop(function.contextClass);
+      if (function.isTopLevel) return isJsInterop(function.library);
+      return false;
+    } else {
+      return _isJsInterop(element);
+    }
+  }
+
+  /// Returns `true` if the name of [element] is fixed for the generated
+  /// JavaScript.
+  bool hasFixedBackendName(Element element) {
+    return isJsInterop(element) ||
+        nativeMemberName.containsKey(element.declaration);
+  }
+
+  String _jsNameHelper(Element element) {
+    String jsInteropName = jsInteropNames[element.declaration];
+    assert(invariant(element,
+        !(_isJsInterop(element) && jsInteropName == null),
+        message:
+            'Element $element is js interop but js interop name has not yet '
+            'been computed.'));
+    if (jsInteropName != null && jsInteropName.isNotEmpty) {
+      return jsInteropName;
+    }
+    return element.isLibrary ? 'self' : element.name;
+  }
+
+  /// Computes the name for [element] to use in the generated JavaScript. This
+  /// is either given through a native annotation or a js interop annotation.
+  String getFixedBackendName(Element element) {
+    String name = nativeMemberName[element.declaration];
+    if (name == null && isJsInterop(element)) {
+      // If an element isJsInterop but _isJsInterop is false that means it is
+      // considered interop as the parent class is interop.
+      name = _jsNameHelper(
+          element.isConstructor ? element.enclosingClass : element);
+      nativeMemberName[element.declaration] = name;
+    }
+    return name;
+  }
+
+  /// Whether [element] corresponds to a native JavaScript construct either
+  /// through the native mechanism (`@Native(...)` or the `native` pseudo
+  /// keyword) which is only allowed for internal libraries or via the typed
+  /// JavaScriptInterop mechanism which is allowed for user libraries.
+  bool isNative(Element element) {
+    if (isJsInterop(element)) return true;
+    if (element.isClass) {
+      return nativeClassTagInfo.containsKey(element.declaration);
+    } else {
+      return nativeMemberName.containsKey(element.declaration);
+    }
+  }
+
+  /// Sets the native [name] for the member [element]. This name is used for
+  /// [element] in the generated JavaScript.
+  void setNativeMemberName(MemberElement element, String name) {
+    // TODO(johnniwinther): Avoid setting this more than once. The enqueuer
+    // might enqueue [element] several times (before processing it) and computes
+    // name on each call to `internalAddToWorkList`.
+    assert(invariant(element,
+        nativeMemberName[element.declaration] == null ||
+        nativeMemberName[element.declaration] == name,
+        message:
+          "Native member name set inconsistently on $element: "
+          "Existing name '${nativeMemberName[element.declaration]}', "
+          "new name '$name'."));
+    nativeMemberName[element.declaration] = name;
+  }
+
+  /// Sets the native tag info for [cls].
+  ///
+  /// The tag info string contains comma-separated 'words' which are either
+  /// dispatch tags (having JavaScript identifier syntax) and directives that
+  /// begin with `!`.
+  void setNativeClassTagInfo(ClassElement cls, String tagInfo) {
+    // TODO(johnniwinther): Assert that this is only called once. The memory
+    // compiler copies pre-processed elements into a new compiler through
+    // [Compiler.onLibraryScanned] and thereby causes multiple calls to this
+    // method.
+    assert(invariant(cls,
+        nativeClassTagInfo[cls.declaration] == null ||
+        nativeClassTagInfo[cls.declaration] == tagInfo,
+        message:
+          "Native tag info set inconsistently on $cls: "
+          "Existing tag info '${nativeClassTagInfo[cls.declaration]}', "
+          "new tag info '$tagInfo'."));
+    nativeClassTagInfo[cls.declaration] = tagInfo;
+  }
+
+  /// Returns the list of native tag words for [cls].
+  List<String> getNativeTagsOfClassRaw(ClassElement cls) {
+    String quotedName = nativeClassTagInfo[cls.declaration];
+    return quotedName.substring(1, quotedName.length - 1).split(',');
+  }
+
+  /// Returns the list of non-directive native tag words for [cls].
+  List<String> getNativeTagsOfClass(ClassElement cls) {
+    return getNativeTagsOfClassRaw(cls).where(
+        (s) => !s.startsWith('!')).toList();
+  }
+
+  /// Returns `true` if [cls] has a `!nonleaf` tag word.
+  bool hasNativeTagsForcedNonLeaf(ClassElement cls) {
+    return getNativeTagsOfClassRaw(cls).contains('!nonleaf');
+  }
+}